The present invention relates generally to photographic film assemblages and, more particularly, to simplified self-developing film assemblages and methods of making the same.
With the increasing growth of digital printing on a variety of low-cost media, conventional photographic film assemblages employing relatively more expensive silver halide emulsions face significant competitive challenges. As a consequence, there is an even keener interest to reduce overall film costs. Such interests are even more pronounced in the area of self-developing film assemblages since the latter include a more complex chemistry, and a complicated film construction for capturing and processing images in a self-contained manner. Further, it is desired to allow the user to remove unneeded portions of the latter type of film unit so that only the image bearing portion remains, thereby giving the impression of a conventional 35 mm print or digital print.
Photographic film assemblages of the self-developing type are well-known in the photographic arts and have been described in numerous patents, such as U.S. Pat. Nos.: 2,612,450; 2,983,606; 3,345,163; 3,362,819; 3,415,644; 3,473,925; 3,594,164; 3,594,165; and, 5,888,693 issued to Polaroid Corporation, Cambridge, Mass., USA. In general, these film constructions employ sophisticated packaged constructions comprising several distinct components united in a relatively complex and costly approach in order to achieve a multiplicity of image capturing and processing functions. For instance, the film assemblage allows storing, spreading, collecting, and retaining of the processing fluid that initiates development of latent images. In particular and in terms of the film structure, each film unit generally includes a photosensitive sheet that captures latent images; a positive receiving sheet for producing the developed image; and, a chemical reagent system including the processing fluid. The fluid is stored in a rupturable container or pod for release and distribution between the photosensitive and positive sheets for initiating diffusion transfer, and a trap is used to capture the processed fluid within the confines of the film unit. The film unit functions to safely store the sensitive chemical compositions during handling and processing; insure that such chemicals effect the desired development without degradation; and, prevent leakage and/or contamination of the chemicals.
In addition, each self-developing film of the above type has a different construction in order to work successfully with a particular camera line of the self-developing type. Thus, for example, 600(trademark) film, commercially available from Polaroid, is designed to be optimized with Polaroid""s 600(trademark) line of cameras and not other camera lines available from Polaroid. In this regard, for instance, the 600(trademark) film would not operate, as intended, in Spectra(trademark) or Captiva(trademark) cameras, nor would the Captiva(trademark) and Spectra(trademark) films work satisfactorily in the 600(trademark) camera line. It will be appreciated, therefore, that each camera line operates with a different film construction.
Despite the multiplicity of known self-developing film constructions and their commercial success, there is, nevertheless, a continuing desire to simplify them as well as concomitantly reduce material and manufacturing costs, yet retain their high degree of integrity and reliability. Furthermore, there is a desire to arrive at a single unified film architecture that is highly versatile from the standpoint of being capable of being used in a variety of existing and future self-developing camera lines of various film sizes. In addition, there is a desire to be able to remove unneeded film parts, such as pod and trap segments for purposes of presenting the resulting developed image area as a 35 mm style print or as a digital print.
In this regard, provision is made to provide a film assemblage of the self-developing type comprising a pair of upper and lower carrier sheets in juxtaposed relationship to one another. A pair of openings is provided in each of the carrier sheets. A photosensitive sheet and a positive receiving sheet are joined to outer surfaces of the upper and lower carrier sheets; respectively, so as to cover the respective openings. The pair of upper and lower carrier sheets is fixedly joined together in overlapping relationship, whereby the photosensitive and receiving sheets are in superimposed and spaced apart relationship thereby forming, in combination, an image area of the film. The combined thickness of the carrier sheets, when joined establishes a mechanical gap between the inner surfaces of the superimposed photosensitive and receiving sheets, which gap allows distribution of the processing fluid therebetween. Leading and trailing pairs of flaps are formed from the carrier sheets adjacent corresponding leading and trailing ends of the image area. The leading pair of flaps, when joined together along their marginal edges, form an enclosure for enclosing a rupturable pod of processing fluid. The trailing pair of flaps when joined together along their marginal edges form an enclosure enclosing a fluid collecting trap. Preselected areas that are located intermediate the image area and the pod, and the image area and the trap are treated with a liquidactivated adhesive. The pod when ruptured allows the processing fluid to flow from the pod into and through the gap of the image area to initiate the diffusion transfer process, and from the gap to a passage leading to the fluid trap. Because of the construction, the flow of processing fluid is relatively uninterrupted relative to known self-developing film systems to enhance uniform distribution and substantially minimize formation of image artifacts. The adhesive is activated in response to contact with the processing fluid flowing thereover, thereby effecting a fluid seal between opposing internal surfaces of the carrier sheets when the latter are pressed together as the film is processed such as when passing through the nip of the usual processing rollers used in processing the film.
The foregoing film assemblage is a highly simplified and unified construction that allows the formation of a mechanical gap that controls the flow of processing fluid in an image area with a significantly reduced number of film components. It is an assemblage that establishes areas between the carrier sheets, which areas in one condition allow the flow of processing fluid therethrough and in another condition are able to have zero gap or clearance that allows the formation of simple and reliable seals at both ends of the gapped image area, after the processing fluid activates adhesives in these areas and is subject to pressure from processing rollers. In addition, sealing the zero gap areas allow for easy removal of the pod and trap ends with substantially reduced or eliminated leakage of any processing fluid from not only the gapped image area but from the severed edges of the pod and trap. In addition, a white bordered area or mask can be created around the image area and is internal to the positive sheet by virtue of a white carrier material being provided, thereby eliminating the need for an external masking element.
Among the objects of the present invention are the provisions for: a) an improved film assemblage that is simplified and less costly in construction, yet is reliable in operation; b) an improved film assemblage that is simplified in construction yet is highly versatile in terms of providing a platform for use in a variety of cameras with different sized films; c) a film assemblage that simply and effectively provides desired spacing and functioning, but yet reduces film costs by eliminating several other components such as rails and mask; d) an improved method for reducing significantly the manufacturing steps for fashioning such a film assemblage of the foregoing types; e) an improved film assemblage that allows a user to remove undesired pod and trap segments; f) a film assemblage whose architecture permits the effective sealing of the flow path of a reagent or processing fluid from pod to trap, everywhere except the image areas so that after tearing, severing or otherwise removing the pod and trap segments, the edges of the image area can be sealed against fluid leakage, possible image artifacts can be eliminated; and, the edges of the torn or severed pod and trap are sealed against leakage of processing fluid: and, g) a mask internal to a positive or image receiving sheet can be created by white carrier material being provided.
The above and other objects and further scope of applicability of the present invention will become apparent from reading a detailed description thereof in conjunction with the drawings wherein like reference numerals indicate like structure throughout the several views thereof.